From 95644099f59087e6c83c7d04747a180ce8955772 Mon Sep 17 00:00:00 2001 From: Curtis McEnroe Date: Sat, 17 Dec 2016 00:18:36 -0500 Subject: Day 14 --- src/bin/day14.rs | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) create mode 100644 src/bin/day14.rs (limited to 'src/bin') diff --git a/src/bin/day14.rs b/src/bin/day14.rs new file mode 100644 index 0000000..b22e88d --- /dev/null +++ b/src/bin/day14.rs @@ -0,0 +1,60 @@ +extern crate crypto; + +use std::collections::VecDeque; +use std::io::{self, Read}; +use std::iter; + +use crypto::digest::Digest; +use crypto::md5::Md5; + +fn md5(salt: &str, index: u32) -> String { + let mut md5 = Md5::new(); + md5.input_str(salt); + md5.input_str(&index.to_string()); + md5.result_str() +} + +fn solve(salt: &str) -> u32 { + let mut hashes = VecDeque::new(); + for i in 0..1001 { + hashes.push_back(md5(salt, i)); + } + + let mut keys = 0; + let mut index = 0; + while let Some(hash) = hashes.pop_front() { + let triple = hash.as_bytes() + .windows(3) + .filter(|w| w[0] == w[1] && w[1] == w[2]) + .map(|w| w[0]) + .next(); + + if let Some(ch) = triple { + let quintuple: String = iter::repeat(ch as char).take(5).collect(); + if hashes.iter().any(|hash| hash.contains(&quintuple)) { + keys += 1; + if keys == 64 { + return index; + } + } + } + + index += 1; + hashes.push_back(md5(salt, 1000 + index)); + } + + unreachable!() +} + +fn main() { + let mut input = String::new(); + io::stdin().read_to_string(&mut input).unwrap(); + + println!("Part 1: {}", solve(input.trim())); +} + +#[test] +#[ignore] +fn part1() { + assert_eq!(22728, solve("abc")); +} -- cgit 1.4.1